Urethane based materials, derivatives, methods of their preparation and uses

Abstract

The invention pertains to the technical field of urethane based materials, in particular to radiation curable urethane precursors that are cross-linkable in solid form and materials obtainable therefrom. In addition the invention pertains to methods for manufacturing these precursors and materials, and their uses. The invention is advantageous to the fields of i.e. coatings and biomedical applications.

What is claimed is: 
     
       1. A (meth)acrylate functional urethane prepolymer, having a ratio r p =h max, solid /h max, molten  equal to or larger than 1, wherein h max, solid  and h max, molten  are the maximum heat flow values of the prepolymer measured by differential photocalorimetry (DPC) at solid state and molten state in nitrogen atmosphere in absence of a photo-initiator and in absence of solvent. 
     
     
       2. The (meth)acrylate functional urethane prepolymer according to  claim 1 , wherein h max, solid  is measured at a temperature of 20° C. and h max molten  is measured at a temperature above the melting temperature of the prepolymer. 
     
     
       3. The (meth)acrylate functional urethane prepolymer according to  claim 1 , characterized in that, the ratio 
       
         
           
             
               
                 r 
                 p 
               
               = 
               
                 
                   h 
                   
                     max 
                     , 
                     20 
                   
                 
                 
                   h 
                   
                     max 
                     , 
                     50 
                   
                 
               
             
           
         
       
       is equal to or larger than 1, and wherein h max, 20  and h max, 50 , are the maximum heat flow values of the prepolymer measured by differential photocalorimetry (DPC) at 20° C. (solid) and 50° C. (molten) in nitrogen atmosphere in absence of a photo-initiator and in absence of solvent. 
     
     
       4. The (meth)acrylate functional urethane prepolymer according to  claim 1 , having the structure: end group-polyisocyanate-backbone-polyisocyanate-end group. 
     
     
       5. The (meth)acrylate functional urethane prepolymer according to  claim 1 , wherein the prepolymer is obtainable as the reaction product of:
 (i) a glycol having a number-average molecular weight of from 390 g/mol to 25000 g/mol, 
 (ii) an polyisocyanate, 
 (iii) a (meth)acrylate functionalized compound comprising at least one group capable of reacting with isocyanate groups, and separated from the (meth)acrylated moiety by a glycol-based spacer. 
 
     
     
       6. The (meth)acrylate functional urethane prepolymer according to  claim 1 , wherein the prepolymer is obtainable as the reaction product of:
 (i) a glycol having a number-average molecular weight of from 400 g/mol to 10000 g/mol, 
 (ii) an polyisocyanate, 
 (iii) a (meth)acrylate functionalized compound comprising at least one group capable of reacting with isocyanate groups, and separated from the (meth)acrylated moiety by a glycol-based spacer. 
 
     
     
       7. The (meth)acrylate functional urethane prepolymer according to  claim 1 , wherein the prepolymer is of formula (Ia) or (Ib), x is 1-10, R 1  is a glycol-based spacer group, R 2  is polyisocyanate derived, and R 3  is a backbone providing compound. 
       
         
           
           
               
               
           
         
       
     
     
       8. The (meth)acrylate functional urethane prepolymer according to  claim 1 , wherein the (meth)acrylate functional urethane prepolymer is the reaction product of a poly(ethylene glycol), poly(ethylene glycol) mono (meth)acrylate and a polyisocyanate. 
     
     
       9. The (meth)acrylate functional urethane prepolymer according to  claim 1 , wherein the (meth)acrylate functional urethane prepolymer is the reaction product of a poly(ethylene glycol), caprolactone (meth)acrylate and a polyisocyanate. 
     
     
       10. The (meth)acrylate functional urethane prepolymer according to  claim 1 , wherein the prepolymer is of formula (II) with n is 45 (PEG 2000), m=6, and x=1-10; n, m and x are average values 
       
         
           
           
               
               
           
         
       
     
     
       11. The (meth)acrylate functional urethane prepolymer according to  claim 1 , wherein the prepolymer is semi-crystalline. 
     
     
       12. A cross-linked material obtainable by curing a (meth)acrylate functional urethane prepolymer according to  claim 1 . 
     
     
       13. The cross-linked material according to  claim 12 , wherein the material is solvent swellable. 
     
     
       14. The cross-linked material according to  claim 12 , wherein the material is water-swellable. 
     
     
       15. The cross-linked material according to  claim 12 , wherein the material was cured in absence of a photo-initiator. 
     
     
       16. A superabsorbent material, an ocular implant, soft tissue regeneration device, cardiovascular device, wound dressing, orthopaedic implant or tissue engineering scaffold, a thermotropic film, a barrier coating, an antifogging coating, a sound damping control, a thermal barrier material, a microwave protection or detection materials, a fire retardant intumescent coating, a membrane for water purification, encapsulation of seeds, soft-feel coatings, surface wrinkling for mat coating, and/or a strippable coating comprising a cross-linked material according to  claim 12 . 
     
     
       17. A method for producing a urethane material, comprising: crosslinking by radiation a (meth)acrylate functional urethane precursor according to  claim 1 , optionally in the presence of a photo-initiator. 
     
     
       18. The method according to  claim 17 , wherein the precursor is in solid form. 
     
     
       19. The method according to  claim 17 , wherein the material is a water-swellable electrospun fibre material obtained from
 (i) electrospinning a solution of a water-soluble prepolymer into an inert gaseous medium to form fibre, and thereafter 
 (ii) cross-linking the fibre to a degree sufficient that the cross-linked fibre is water-insoluble. 
 
     
     
       20. The method according to  claim 19 , wherein the cross-linking is in absence of a photo-initiator and/or in absence of a solvent.